The problem of how to increase motor output power is one of the key technologies that have been innovated, developed and improved since the advent of the motor. In general, the output power of the motor may be increased by directly increasing the size of the motor; however, this way may cause the weight and volume of the motor to increase while the power of the motor is increased. Thus, not all household items or industrial appliances can directly increase the output power of products by increasing the size of the motor. Therefore, how to improve the energy conversion efficiency of the motor is an important research and development direction for those skilled in the art.